This invention relates to a glassware manufacturing method in which an air bubble is encapsulated in a thick part of the bottom of the glassware and also relates to a gob feeder having an air injection means to be used for carrying out this method.
To further the ornamentality of glassware items in addition to their ornamental shapes, there have been practiced various methods for forming voids within thick parts of them to utilize the refraction and reflection of glass by taking advantage of the transparency of glass. Of these methods, a method of enclosing air within a thick part of the bottom of a glassware item to form an air bubble therein has long been practiced.
The conventional method of forming an air bubble within a thick part of the bottom of a glassware has been carried out by manually enclosing air in the thick part of the bottom during a process of forming the glassware. The conventional manual method has low production efficiency and also requires a high degree of skill.
It is an object of this invention to provide a glassware manufacturing method in which an air bubble is injected into a molten charge of glass as it is being formed into a gob which is subsequently formed into a finished article using either an automatic pressing machine such as a Lynch press machine or a machine called Hartford H-28 or an automatic press-and-blow molding machine.
It is another object of this invention to provide a gob feeder with an air bubble injection device which uniformly positions air bubbles in successive charges of molten glass as they are being formed into gobs.